1. Field of the Invention
The present invention relates to an antenna device that includes a plurality of coils for different systems, such as a non-contact charging coil and a near field communication coil, and an electronic device that includes the antenna device.
2. Description of the Related Art
A module that includes a communication device, such as a mobile terminal, equipped with a near field communication (NFC) coil, which uses radio waves of an HF (13.56 MHz) band, and with a non-contact charging coil is disclosed in Japanese Unexamined Patent Application Publication No. 2013-121248 and Japanese Unexamined Patent Application Publication No. 2013-169122.
In the module disclosed in Japanese Unexamined Patent Application Publication No. 2013-121248, the non-contact charging coil and the NFC coil, each of which has a rectangular spiral shape, are superposed with each other so as to be concentric with each other.
In the module disclosed in Japanese Unexamined Patent Application Publication No. 2013-169122, the non-contact charging coil and the NFC coil are arranged so that the axes of the coils are perpendicular to each other.
In the module disclosed in Japanese Unexamined Patent Application Publication No. 2013-121248, since the non-contact charging coil and the NFC coil are coaxial with each other, and their coil conductors are arranged so as to be close to each other, there is a concern that a non-contact charging circuit and an NFC circuit may interfere with each other due to coupling of the coils.
In the module disclosed in Japanese Unexamined Patent Application Publication No. 2013-169122, since the non-contact charging coil and the NFC coil are arranged so that the axes of the coils are perpendicular to each other, the coils are less likely to be coupled to each other. Thus, it is less likely that interference between a non-contact charging circuit and an NFC circuit will occur. However, there is a limitation on the shape of the NFC coil and on how the NFC coil is wound, and there are problems in that the size (height) of the NFC coil is likely to increase, and in that the degree of freedom when designing the NFC coil is small.